1. O. Funayama, M. Arai, Y. Tashiro, H. Aoki, T. Suzuki, K. Tamura, H. Kaya, H. Nishii and T. Isoda, J. Ceram. Soc. Jn 98 (1990) 104.
2. G. E. Legrow, T. F. Lim, J. Lipowitz and R. S. Reaoch, Am. Ceram. Soc. Bull 66 (1987) 363.
3. D. Seyferth and G. H. Wiseman, in ?Ultrastructure Processing of Ceramics, Glasses and Composites?, edited by L. L. Hench and D. R. Ulrich (Wiley-Interscience, New York, 1984) p. 265.
4. K. B. Schwartz, D. J. Rowcliffe, Y. D. Blum and R. M. Laine, in ?Proceedings of the Materials Research Society Symposium?, Palo Alto, April 1986, edited by C. Brinker, D. Clark, and D. Ulrich (Materials Research Society, Pittsburg, PA, 1986) p. 407.
5. D. Seyferth, G. H. Wiseman and C. Prud'homme, J. Am. Ceram, Soc. 66 (1983) C 13.